The present invention relates to novel amine group containing polyether polyols and to a process for their preparation. These novel amine group containing polyether polyols contain at least one terminal hydroxyl group, at least one pendant amine group, and have molecular weights of from about 105 to about 35,000. The novel process comprises reacting a compound containing one or more hydroxyl group with an epoxide which contains at least one halogen atom, in the presence of one or more double-metal cyanide catalysts to form an intermediate polyether polyol containing halogenated carbon atoms, and reacting this intermediate polyether polyol with a primary, secondary or tertiary amine group containing compound.
Polyether polyols are known in the art for the preparation of a variety of polyurethanes. The polyether polyols are typically prepared by reacting a polyhydric alcohol such as sucrose, diethylene glycol, trimethylolpropane, etc., with an alkylene-oxide such as, for example, ethylene oxide or propylene oxide, in the presence of an alkaline catalyst such as sodium hydroxide. After reaction, the alkaline catalyst is typically removed by one of various methods. Suitable processes for the production of polyether polyols and removal of catalyst residues as are described in, for example, U.S. Pat. Nos. 3,000,963, 3,299,151, 4,110,268, 4,380,502 and 4,430,490.
Other known polyether polyols include the so-called amine-initiated polyether polyols as well as the amine-terminated polyether polyols. Amine-intiated polyether polyols have hydroxyl end groups and one or more amine groups as part of the polyether backbone. Amine-terminated polyether polyols have a conventional polyether backbone and contain at least about 50% by weight of amine groups in terminal positions.
Amine-initiated polyether polyols and processes for their production are known and described in, for example, U.S. Pat. Nos. 4,877,879 and 5,786,405, and Japanese Abstracts 57168917A and 57168918. These polyether polyols show promising results in foam-forming systems blown without CFC blowing agents. Such polyether polyols can be formed by reacting an amine such as, for example, ethylene diamine or toluene diamine, with an alkylene oxide such as, for example, ethylene oxide or propylene oxide. Overall, this process is quite similar to the conventional process of preparing a polyether polyol, except the initiator contains one or more amine group. The reaction may also be catalyzed with an alkaline catalyst such as potassium hydroxide. The addition of conventional antioxidants such as, for example, butylated hydroxyl toluene (BHT) to the resultant amine-initiated polyether polyols is necessary to minimize color formation in the polyether polyols and foams produced therefrom.
There are several known processes for preparing amine-terminated polyether polyols. These include, for example, U.S. Pat. Nos. 3,654,370, 3,666,726, 3,691,112, 5,043,472, 4,902,768, 5,015,774 and 5,693,864. Amine-terminated polyether polyols may be prepared by, for example, reacting a polyol with ammonia under catalyzed high temperature conditions, reacting a polyfunctional acetoacetic acid ester with a polyfunctional amine, by catalytic amination of a suitable polyol by reacting the polyol with a primary or secondary amine in the presence of a catalyst, by reacting a polyoxyalkylene polyol with a primary amine in the presence of a suitable catalyst, or by reacting a polyether containing multiple leaving groups with a primary amine or ammonia.
U.S. Pat. Nos. 4,156,775 and 4,198,269 relate to quaternary ammonium salts of epihalohydrin polymers. These are prepared by first reacting epichlorohydrin (i.e. ECH) with, e.g. diglycidyl ether of BPA (see Example 1 in the '269 patent) in the presence of water and BF3, followed by making a 25% solution of the polymer by dissolving it in acetonitrile, cooling, and adding anhydrous dimethylamine to the solution. The disadvantage of alkoxylation catalyst described therein is that cationic alkoxylation catalysts such as BF3, are strongly acidic, and always yield cyclic oligomers of the alkyene oxides, regardless of the catalyst concentration. The cyclic oligomers are difficult to remove completely and impart a strong odor to the resultant polyether polyol product, even when the cyclic oligomers are present at low parts per million (ppm) levels.
Advantages of the presently claimed polyether polyols include the ability to intersperse functional groups (e.g. chloride, bromide, etc.) throughout the polyether molecule with little or no side products and no degradation of the functional groups during alkoxylation. This allows the formation of polyethers which contain varying amounts of pendant amine groups, as well as flexibility in the functionality of the amine group itself (i.e. primary, secondary, tertiary, or quaternary amine groups).